A band-type wireless communication device to be worn for use on, for example, an arm includes an antenna device disposed inside the band or built in a housing for compactness or portability of the band-type wireless communication device.
Patent Literature 1 discloses an antenna device for a wristwatch-type wireless communication device which antenna device is arranged to reliably produce high antenna gain and good antenna directivity while the wristwatch-type wireless communication device is worn on an arm. The antenna device of Patent Literature 1 for a wristwatch-type wireless communication device includes a helical antenna built in a main body of the wristwatch. The antenna device includes a means for, in the state where the wristwatch is worn on an arm and placed in front of the human body, (i) positioning the helical antenna away from the human body in the front direction, (ii) orienting the helical antenna so that its axis direction is perpendicular to a main printed circuit board oriented substantially parallel to the arm, and (iii) connecting the helical antenna to the main printed circuit board. The antenna device assumes the arm to serve as an earth conductor for the helical antenna and operates in such a manner that the helical antenna has a main polarization direction perpendicular to the arm. Since the antenna device assumes the arm to serve as an earth conductor for the helical antenna and operates in such a manner that the helical antenna has a main polarization direction perpendicular to the arm, the antenna device prevents the gain from being reduced when the wristwatch is worn on an arm.